The present invention relates to a new and improved method of, and apparatus for, measuring the moisture content or dampness of textile structures, especially textile webs.
The textile moisture regulators heretofore known, operating according to the conductance measuring principle, have only been able to fulfill their function to a limited extent, particularly since the use of synthetic textile fibers. Thus, the input circuit formed by a voltage divider composed of the oftentimes extremely high current-flow resistance of the textile web and a limited high ohm fixed resistor, with voltage divider ratios beginning at about 1:100 and 100:1 no longer allow for any signal evaluation. The resistances which are standard with synthetic textiles, up to approximately 10.sup.12 ohms, result in voltage divisions which are greater by a number of decades than those indicated. A corresponding increase of the fixed resistance, as a general rule, cannot be realized due to the limited resistance of the insulating material and the amplifier inputs.
Apart from these limitations of the measurement range there also come into play the ripple or noise due to the extremely high ohmic and long infeed lines as well as falsification of the measuring signal by fault or error currents, caused by the high static charges of the moved textile webs. These discharge currents are oftentimes of the same order of magnitude or even greater by several picoamperes, than the measuring currents conventional for dry synthetics, and thus, make it impossible to carry out reliable measurement of such materials.